216909987840 has 1440 divisors, whose sum is σ = 958373410176. Its totient is φ = 44166021120.

The previous prime is 216909987797. The next prime is 216909987887. The reversal of 216909987840 is 48789909612.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3555901410 + ... + 3555901470.

Almost surely, 2^216909987840 is an apocalyptic number.

216909987840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216909987840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (479186705088).

216909987840 is an abundant number, since it is smaller than the sum of its proper divisors (741463422336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216909987840 is a wasteful number, since it uses less digits than its factorization.

216909987840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 144 counting only the distinct ones).

The product of its (nonzero) digits is 15676416, while the sum is 63.

The spelling of 216909987840 in words is "two hundred sixteen billion, nine hundred nine million, nine hundred eighty-seven thousand, eight hundred forty".